Radiocommunication



Patented Jan. 2, 1923.

"entree stares arser oerice,

CHARLES VEYNE LOGWOOD, OF CHICAGO, ILLINOIS, ASSIGNOR TO FOREST RADIO TELEPHONE & TELEGRAPH COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

RAnmcoMMUNIoATIoiv.

Application filed July 2, 1921. Serial No. 482,035.-

To all whom "it may concern Be it known that 1, CHARLES V. Loewoon,

a citizen of the United States, residing at Chicago, in the county of Cook, State of Illinois, have made a certain new and useful invention in Radiocommunication, of which the following is a specification. This invention relates to radio communication, and is particularly directed to systerms that are employed for the transmission of signals through the medium of high frequency currents. I

The object of the invention is to provide a signaling system which is simple and eflicient and economical in manufacture.

A further object of the invention is to provide a system of the character set forth wherein the electrical power of radiation is materially increased.

A further object of theinvention 'is to provide a system which will lengthen the distance of transmission of signals, such as wireless telephone, without distortion, to a distance greater than has heretofore been obtained with simplenon-comp-licated circuits. Further objects of the invention will appear more fully hereinafter.

My invention consists substantially in the 3 combination, construction, location andrelative arrangement of parts and circuits employed in connection therewith, all as will be'more fully hereinafter set forth, as shown in the accompanying drawings and finally pointed out in'the claims.

Referring now to the drawings,-

Fig. 1 is a diagrammatic view illustrating a circuit arrangement embodying my invention, showing the same in connection with a wireless telephone transmitter system;

Fig. 2 is a similar view for a slightly modified arrangement showing in addition to the telephone circuit a wireless telephone transmitter system;

Fig. 3 is a similar View showing a still further modified arrangement; and

Fig. 4 is a similar view showing a modification of the type of resistance path that is employed in accordance with my invention.

The same part is designated by the same reference character wherever it occurs throughout the several views.

Referring to Fig. 1,-I show an insulating 55' circuit of the open radiating type, comprising the antenna 1, the inductances 2, 3, condenser 4, and earth connection 5. The primary circuit includes inductances 6 and 7 inductively associated with inductances 2, 3, of the radiating circuit and condenser 8," and vacuum tubes 9 and 10. Each of the vacuum tubes contain or have associated therewith the usual three electrodes, namely, the ,filament electrode 11, and the plate electrode 12 and the intermediateor grid electrode 13. The grid electrodes of the two tubes 9, 10, are connected to each other through the inductance 14, whichis inductively associated with the coils2, 6, 7 and 3, as shown. The vacuum tubes 9 and 10 are connected in shunt to the coils 6, 7, and the condenser 8. The filament electrodes 11 of the vacuum tubes v 9 and 10 are connected iii parallel, and are heated from a common source, for example, the battery 15. All connections to the inductances 2, 6, 7 and 3 are adjustable, as indicated, and the inductance 14 has an adjustable tap connection including a choke coil 16leading to the filament electrode 17 of a vacuum tube 18, which filament, electrode 17 is heated from a suitable source, for example, battery 15. The plate electrode 19 of vacuum tube 18 is connected to one leg of the filaments-l1 of the tubes 9, 10. The grid electrode 2.0 of the vacuum tube 18 is connected to its filament 17 through the transformer coil 21. With this arrangement it will be apparent that there is no conductive connection between the grid electrodes 13 of vacuum tubes 9 and 10 and any other electrode or electrodes thereof, the only connections effected being the inductive relation between the grid and.

plate electrodes and the high resistance leakage path existing between the filament and the plate electrodes of the vacuum tube 18 in the evacuated vessel thereof. Current is supplied to the plate electrodes 12 of the vacuum tubes 9, 10, from a suitable source of current, for example, generator 23, shunted by condensers 24 25. One terminal, usually the negative terminal of the current source 23, is connected to; one leg of the filaments 11 of the vacuum tubes 9 and 10, through the choke coil 24, and the other terminal is connected through the choke coil 25 to the respective plate elec trodes 12 of the vacuum tubes 9 and 10, thereby constituting the usual B battery circuit of the oscillating audion circuit. The choke coils 25 and 24: tend to filter out excessive currents. Choke coil 16 prevents high frequency currents from passing through .the leakage ath and the condensers 2 1 and 25 absorb c ianges of commutator ripples.

I have found this circuit to be an e-Xoeptrodes 13 of the vacuum tubes 9 and 10, by

inducing an opposite potential, thereby causing the current to increase or decrease in the plate electrodes 12 of the respective tubes 9 and 10. An increase of positive potential on one grid electrode 13 increases the plate current, while in the other tube a negative charge is impressed on the grid, which further deflects the current to the other tube until the oscillation completesthecycle and reverses the process causing a shift of the polarity whichin turn reacts throughout the circuit. Thus it will be seen that the grid electrode 13 of one tube is always influenced by the opposite tube. It will be' apparent that through the operation of oscillation there is a necessity for equalizing the negative charge on the grid electrodes 13, and to accomplish this I employ a resistance. It is obvious that a. high resistance is necessary, and, for that reason, I employ the resistance represented by the evacuated space between the filament 17 and the plate 19 of the vacuum tube 18. The current source 15 which: heats the filament 17 of the vacuum tube 18 is isolated from the ground and is connected through the choke coil 16 to the grid electrodes 13 of the vacuuintubes 9 and 10, as hereinbefore described, Thus a positive potential is impressed on the plate electrode 19 of the tube 18from a current source 15 employed for heating the filaments 11 of the tubes 9 and 10, so that the internal resistance of the tube is sufficient to prevent short circuiting the filaments 11 to grids 13, as in power transmission sets this must be avoided, and excessive grid current-s must necessarily be checked. Where the system is to be employed for telephone transmission, the primary coil 30 which is inductively associated with the coil 21 connected between the grid 20 and filament 17 of vacuum-tube 18, is" connected through microphone 31, which derives its current as illustrated, though to these variations I do not desire to be limited or restricted, from the current source 15, whichis employed to heat the filament 11 of the vacuum. tubes 9 and 10. When words are spoken in the microphone 31, currents are induced through the transformer 30, 21, to the grid 20 of vacuum tube 18, thus stopping or increasing the leak current which passes from the filaments 11 of vacuum tubes 9 and 10 through the plate electrode 19 of tube 18 to the grid electrodes -transmitted through the radiating system 1 to 5, and, of course, at the receiving end.

accordingly.

With this circuit I have found it possible to transfer through the prim: y oscillating circuit with only 8 micro-henries of induct ance with an efficiency of per cent output to input, using a capacity of .008 microfarads across the plates. This inductance corresponds to one and a half turns of a helix 8 inches in diameter, thus a. frequency of two million is easily obtained without any damage to the power tubes employed for generating the high frequency currents.

I have found that it is advisable thatthe tubes 9 and 10 be so associated to the inductances employed that the plate of one illustrating the application of the system to wireless telegraphy, and also to show a modification as to the means employed for lighting the filaments of the respective vacuum tubes 9, 10 and 18. It will be observed that the circuit arrangements of the vacuum tubes 9 and 10 are the same-in this figure as described in connection with Fig. 1, with the vacuum tube 18 connected between-the grids and filaments of the respective vacuum of an alternating current generator 33,-

whereby alternating current is supplied through a transformer 32,- 31 to the filaments 11, to light the same. Alternating current 33 is also connected in shunt t5 the primary coil 3% of the transformer, the secondary coil, 35, of which is connected in series with the filJa-ment electrodes 17 of the vacuum tube 18 whereby the filament 17 is supplied with heating current, as will be obvious. In this arrangement the microphone 31 is connected in a microphone circuit supplied with current from a suitable source such as the battery 15. "When it is desired to use this circuit and system for radio telegraphitransmission I have found it efiicient to connect the telegraph key as shown between the grids 13 and the filaments 19 being connected to the filament electrode ent. I have also incorporated in this view the modification wherein the inductive coupling between the antenna earth circuit and the plate circuit of the vacuum tubes 9 and 10, is modified to a conductive Coupling therebetween, thereby enabling the elimination of inductance coils 6 and 7.

In Fig. 4 I have shown an arrangement for effectively increasing sensitiveness of modulation effected by the microphones 31, where exceedingly high power is being gencontrolled by the microphone, the grid electrode 20 is insulated from its filament by the vacuum of tube 18*, the grid filament circuit 20, 17*, thereof being directly controlled" by the microphone circuit 15 30, through the transformer 21, 30*, the plate electrode 17 of vacuum tube 18.

Many other modifications and changes in details will-readily occur to those skilled in the art without departing from the spirit and scope of my invention as defined in the claims and shown in the accompanying drawings, and I, therefore, desire to have the foregoing description and the drawings used in connection therewith regarded in an illustrative rather than in a limiting sense; but having now set forth the objects and nature of my invention, and having shown and described circuits 'showing the embodiment theroef, what I claim as new and useful and desire to secure by Letters Patent is:

1, A radio signaling system, comprising an antenna earth system, a plurality of vacuum tubes having hot and two or more cold electrodes, means for associating said cold electrodes with said antenna earth system, and with said hot electrodes, and a vacuum tube interposed between one set of cold electrodes and the filament electrodes whereby the space between the electrodes of said last mentioned vacuum tube constitutes a. resistance in the circuit between said set of cold electrodes and the filament electrodes,

-and means for varying the conductivity of the space of the vacuum tube by and in accordance with signals.

2. A radio signaling system, comprising an antenna earth system, a plurality of vacuum tubes having hot and two or more cold electrodes, means for associating said coldelectrodes with said antenna earth sys-.

tem, a circuit connecting one set of said cold electrodes with said hot electrodes including a high resistance, and means for varying said resistance by and in accordance with signals.

3. A radio signaling system comprising an antenna earth system, a plurality of audions having plate, grid and filament electrodes associated therewith," a circuit connecting said plate electrodes to each other and to said filament electrodes, a circuit connecting said grid electrodes to each other, a circuit connected between said grid electrodes and said filament electrodes and including therein a resistance, and means for varying said resistance by and in accordance with signals.

4. A radio signaling system comprising an antenna earth system, a plurality of audions having plate, grid and filament electrodes associated therewith, a circuit connecting said plate electrodesto each other and to sa1d filament electrodes, a circuit connecting said grid electrodes to each other, a circuited connected between said grid electrodes and said filament electrodes and including therein a resistance, and means for varying said resistance by and in accordance with signals, and means for associating said audions with said antenna earth system.

5. A radio signaling system comprising an antenna earth system, a plurality of audions having plate, grid and filament electrodes associated therewith, a circuitconnecting said plate electrodes to each other and to said filament electrodes, a circuit connecting said grid electrodes to each other,-

an antenna earth system, a plurality of audions having plate, grid and filament electrodes associated therewith, a circuit connecting said plate electrodes to each other and to said filament electrodes, a circuit connecting said grid electrodes to each other, a circuit connected between said grid electrodes and said filament electrodes and including therein a resistance, and means for varying said resistance by and in accordance with signals, and means included in said plate and grid circuits for associating said audions with said antenna earth system and with each other. I

7. A radio signaling system comprising an antenna earth system, a plurality of audions having a plate, grid and filament electrodes associated therewith, a circuit connecting said plate electrodes to each other and to said filament electrodes, a circuit connecting said grid electrodes to each other, a circuit connected between said grid electrodes and said filament electrodes and including therein a vacuum space, and means for varying' the conductivity of said vacuum space by and in accordance with signals.

8.-A radios'ignaling system comprising an antenna earth system,- a plurality of audions having plate, grid and filament electrodes associated therewith, av circuit connectingsaid plate electrodes to each other and to said filament electrodes, a circuit connecting said grid electrodes to each other, a circuit connected between said grid .electrodes and said filament electrodes and including therein a vacuum space and means for varying the conductivity-of said vacuum space by and in accordance with signals, and means for associating said audions with said antenna earth system. 9. A radio slgnallng system comprising an antenna earth system, a plurality of audions having plate, grid and filament electrodes associated therewith, a circuit connecting saidplate electrodes to each other and to said filament electrodes, a circuit con necting said grid electrodes to each other, a circuit connected between said grid electrodes and said filament electrodes and in-..

cluding therein a vacuum space, and means for varying the conductivity of said vacuum space by and in accordance with signals, and means included in said plate and grid circuits for associating said audions with said antenna earth system.

10. A radio signaling system comprising an antenna earth system, a plurality of audions having plat-e, grid and filament electrodes associated therewith, a circuit connecting said plate electrodes to each other and to said filament electrodes, a circuit connecting said grid electrodes to each other, a circuit connected between said grid electrodes and said filament electrodes and including therein a vacuum space, and means 11. A radio signaling system comprising an antenna earth/ system, a plurality of audions having plate, grid and filament electrodes associated therewith, a circuit connecting-said plate electrodes to each other and to said filament electrodes, a circuit connecting said grid electrodes to each other,

a circuit connected between said grid electrodes and said filament electrodes and including therein'the separated electrodes of a vacuum tube, and means for varying the conductivity of the space between the electrodes of said vacuum tube by and in ac cordance with signals.

12. A radio signaling system comprising an antenna earth system, a plurality of audions having plate, grid and filament electrodes associated therewith, a circuit connecting said plate electrodes to each other.

. and to said filament electrodes, a circuit connecting said grid electrodes to each other,

a circuit connected between said grid electrodes and said filament electrodes and including therein the separated electrodes of a vacuum tube, and means for varying the conductivity of the. space between the electrodes of said vacuum tube'by and in accordance with signals, and means for associating said audions with said antenna earth system.

- 13. Aradio signaling system comprising an antenna earth system, aplurality of audions having plate, grid and filament 'electrodes associated therewith, a circuit connecting said plate electrodes to each other and to said filament'electrodes, a circuit 'connecting said grid electrodes to each other, a circuit connected between said grid electrodes and said filament electrodes and including therein the separated electrodes of a vacuum tube, and means for'varying the conductivity of the space between the electrodes of said vacuum tube by and in accordance with signals, and' means included in said a to said filament electrodes, a circuit connecting said grid electrodes to each other, a circuit connected between said grid electrodes and said filament electrodes and including therein the separated electrodes of a vacuum tube, and -means for varying the conductivity of the space between the electrodes of said vacuum tube by and in accordance with signals, and with each other.

15. A radio signaling system comprising an antenna earth system, a plurality of audions having plate, grid and filament electrodes associated therewith, a ci'rcuit connecting said plate electrodes to each other and to said filament electrodes, a circuit connecting said grid electrodes to each other, a circuit connected between said grid electrodes and said filament electrodes and including therein the filament and plate electrodes of an auxiliary audion, and means for impressing a signal current upon the rid electrode of said auxiliary audion.

16. A. radio signaling system comprising an antenna earth' system, a plurality Ogf audions having plate, grid and filament electrodes associated therewith, a circuit connecting said plate electrodes to each other and to said filament electrodes, a circuit connecting said grid electrodes to each other, a circuit connected between said grid electrodes and said filament electrodes and including therein the filament and plate electrodes of an auxiliary audion, and means eluding therein the filament and plate electrodes of an auxiliary audion, and means for impressing a signal current upon the grid electrode of said auxiliary audion, and -means included in said plate and grid cir- .cuits for associating said audions'with said antenna earth system.

18. A radio "signaling system comprising an antenna earth system, a plurality of audions having plate, grid and filament electrodes associated therewith, a circuit connecting said plate electrodes to each other and to said filament electrodes, a circuit connecting said grid electrodes to each other, a circuit connected between said grid electrodes and said filament electrodes and including therein the filament and plate electrodes of an auxiliary audion, and means for impressing a signal current upon the grid electrode of said auxiliary audion, andwith each other.

19. A radio signaling system comprising an antenna earth system, a plurality of audions having plate, grid and filament electrodes associated therewith, a circuit con necting said plate electrodes to each other and to said filament electrodes, a circuit connecting said grid electrodes to each other, a circuit connected between said grid electrodes and said filament electrodes and including therein the separated electrodes of a vacuum tube, and means for varying the conductivity of the space between the electrodes of said vacuum tube by and in accordance with signals, and means for heating the hot electrodes of said audions and said vacuum tube from .the same source of current.

20. A radio signaling system comprising an antenna earth system, a plurality of audions having plate, grid and filament electrodes associated therewith, a circuit connecting said plate electrodes to each other and to said filament electrodes, a circuit connecting said grid electrodes to each other, a circuit connected between said grid electrodes and said filament electrodes and including therein the separated electrodes of a vacuum tube, and means forvarying the conductivity of the space between the electrodes of said vacuum tube by and in accordancewith signals, and means for associating said audions with said antenna earth system, and means for heating the hot electrodes of said audions and said vacuum tube from the same source of current.

21. A radio signaling system comprising an antenna earth system, a plurality of andions having plate, grid and filament electrodes associated therewith, a circuit connecting said plate electrodes to each other and to said filament electrodes, a circuit connecting said grid .electrodes to each other, a circuit connected between said grid electrodes and .said filament electrodes and in cluding therein the separated electrodes of a vacuum tube, and means for varying the conductivity of the space between the electrodes of said vacuum tube by and in ac cordance with signals, and means included in said plate and grid circuits for associating said audions with said antenna earth system, and means for heating the hot electrodes of said audions and said vacuum tube from the same source of current.

22. A radio signaling system comprising an antenna earth system, a plurality of audions having plate, grid and filament electrodes associated therewith, a circuit connecting said plate electrodes to each other and to said filament electrodes, a. circuit connecting said grid electrodes to each other, a circuit connected between said grid electrodes and said filament electrodes and iiicluding therein the separated electrodes of a vacuum tube, and means for varying the conductivity of the space between the electrodes of said vacuum tube by and in accordance with signals, and with each other, and means for heating the hot electrodes of said audions and said vacuum tube from the same source of current. i

28. A radio signaling system comprising an antenna earth system, a plurality of andions having plate, grid and filament electrodes associated therewith, a circuit connecting said plate electrodes to each other and to said filament electrodes, a circuit connecting said grid electrodes to each other, a circuit connected between said grid electrodes and said filament electrodes and including therein the filament and plate electrodes of an auxiliary audion, and means for impressing a signal current upon the grid electrode of said auxiliary audion, and means for heating the filament electrodes of all of said audions from the same source of current. i

'24. A radio signaling system comprising an antenna earth system, a plurality of andions having plate, grid and filament electrodes associated therewith, a circuit connecting said plate electrodes to each other and to said filament electrodes, a circuit connecting said grid electrodes to each other, a circuit connected between said grid electrodes and said filament electrodes and ineluding therein the filament and plate electrodes of an auxiliary audion, and means for impressing asignal current upon the grid electrode of said auxiliary audion, and means for associating said audions with said antenna earth system, and means for heating the filament electrodes of all of said audions from the same source of current.

25. A radio signaling system comprising an antenna earth system, a plurality of audions having plate, grid and filament electrodes associated therewith, a circuit connecting said plate electrodes to each other and to said filament-electrodes, a circuit con- .necting said grid electrodes to each other,

a circuit connected between said grid electrodes and said filamentelectrodes and including therein the filament and plate electrodes of an auxiliary audion, and means for impressing avsignal current upon the grid electrode of said auxiliary audion, and

trodes associated therewith, a circuit connecting said plate electrodes to each. other and to said filament electrodes, a circuit connecting said grid electrodes to each other, a circuit connected between said grid electrodes and said filament electrodes and including therein the filament and plate electrodes of an auxiliary audion, and means for impressing a signal current upon the grid electrode of sald auxiliary audion, and

with each other, and means for heating the filament electrodes of all of said audions from the same source of current.

In testimony whereof I have hereunto set my hand on this 23rd day of'June, A. D.,

CHARLES VEYNE LOGWOOD, 

